MLCC product

Abstract

The invention relates to the technical field of multilayer ceramic capacitors, in particular to an MLCC product. The MLCC product comprises a plurality of blank dielectric layers and a plurality of inner electrode layers which are alternately stacked along a lamination direction, and a first end electrode and a second end electrode which are respectively positioned at two sides of the inner electrode layers, the inner electrode layer comprises a first type electrode layer and a second type electrode layer which are arranged in a crossed manner and are respectively connected to the first end electrode and the second end electrode; the stacking sequence of the inner electrode layers comprises at least one strengthening section in the stacking direction, and in the strengthening section, the number of at least one continuously arranged inner electrode layer of the same type is not less than 2. The MLCC product has a new stacking design, the sintering strength of the strengthening section can be improved, the voltage endurance capability and the current endurance capability of the strengthening section are improved, the failure rate in a voltage endurance experiment and a high-temperature and high-pressure experiment is reduced, and therefore the consistency and the reliability of the MLCC product are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip multilayer ceramic capacitors, in particular to a MLCC product. BACKGROUND

[0002] Multi-layer Ceramic Capacitors (MLCC) is a kind of capacitor with ceramic as dielectric material and multi-layer stacked structure. MLCC has the advantages of small size, large capacity, high temperature resistance, good high frequency characteristics, etc., and can be applied to various circuits such as oscillation circuit, timing or delay circuit, coupling circuit, decoupling circuit, etc., and is widely used in consumer electronics, vehicle electronics, base station, server and security industry.

[0003] In the design of MLCC product, in addition to the size, the capacity and voltage are the most important parameters. In the application of circuit, the performance requirements of MLCC product are higher and higher, and high-capacity and high-voltage products need to be designed to meet the application of high-end field. However, the failure rate of conventional high-capacity and high-voltage products in voltage resistance experiment and high temperature and high pressure experiment is high, which seriously affects the consistency and reliability of the product. SUMMARY

[0004] Therefore, it is necessary to provide a MLCC product to solve the problem of high failure rate of conventional high-capacity and high-voltage products in voltage resistance experiment and high temperature and high pressure experiment.

[0005] The above-mentioned purpose of the present application is realized by the following technical scheme: The present application provides a MLCC product, comprising a plurality of blank dielectric layers (30) and a plurality of internal electrode layers (40) which are alternately stacked along the stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layer (40), the internal electrode layer (40) comprises a first type electrode layer (A) and a second type electrode layer (B) which are cross arranged and respectively connected to the first end electrode (11) and the second end electrode (12). The stacking sequence of the internal electrode layer (40) contains at least one reinforced section (50) in the stacking direction, and the number of the same type of internal electrode layer (40) continuously arranged in the reinforced section (50) is not less than 2.

[0006] In one embodiment, the reinforced section (50) is located in the central region of the MLCC product in the stacking direction.

[0007] In one embodiment, the stacking sequence of the reinforced section (50) is a symmetric sequence, and the number of continuously arranged first type electrode layer (A) is equal to the number of continuously arranged second type electrode layer (B).

[0008] In one embodiment, the symmetric sequence is (AABB)xn1, (AABB)xn1-AA or BB-(AABB)xn1, wherein n1 is a positive integer.

[0009] In one embodiment, the MLCC product further comprises a standard section (60) on both sides of the reinforced section (50), in which the first type of electrode layer (A) and the second type of electrode layer (B) are stacked in a single alternating manner.

[0010] In one embodiment, the total thickness of the reinforced section (50) is not less than 25% of the total thickness of the standard section (60).

[0011] In one embodiment, the total thickness of the reinforced section (50) is greater than 100 μm.

[0012] In one embodiment, the stacking sequence further comprises at least one medium interlayer section (70) comprising at least two layers of continuous blank medium layers (30) and located within the reinforced section (50).

[0013] In one embodiment, the stacking sequence further comprises at least one medium interlayer section (70) comprising at least two layers of continuous blank medium layers (30) and located between the reinforced section (50) and the standard section (60).

[0014] In one embodiment, the stacking sequence further comprises a lower protective cover (22) at the lowermost layer and an upper protective cover (21) at the uppermost layer, both of which are stacked by a plurality of blank medium layers (30).

[0015] The present application has at least the following beneficial effects: In the MLCC product provided by the present application, the stacking sequence of the internal electrode layer (40) comprises at least one reinforced section (50) in the stacking direction, in which the number of continuously arranged internal electrode layers of the same type is not less than 2, which can play the following roles: First, the continuously arranged internal electrode layers (A and / or B) of the same type are changed from 1 to 2 or more, which is equivalent to an increase of 1 times of metal electrode (or an increase of 1 times of wire diameter), so that the withstand voltage of the internal electrode layer (40) in the reinforced section (50) is increased, and the reliability is enhanced.

[0016] Second, in the conventional high-capacitance high-voltage design, except for the two outermost inner electrode layers (40), the rest of the inner electrode layers (40) are the common electrodes of two adjacent capacitors, and one inner electrode layer (40) bears the current of two capacitors. In the reinforced section (50) of the present application, the number of continuously arranged inner electrode layers of the same type is increased, which plays a role of current distribution, and each inner electrode layer (40) only needs to bear the current of one capacitor. The current borne by the inner electrode layer (40) is smaller, which reduces internal heating and loss, effectively reducing the problem of inner electrode layer (40) melting breakdown caused by high temperature.

[0017] Third, during the glue discharge process, the number of continuously arranged inner electrode layers of the same type is increased, which is equivalent to increasing multiple outward glue discharge channels in the reinforced section (50). Organic matter will be discharged along the direction of the inner electrode layer (40), reducing the organic matter in the reinforced section (50), thereby reducing the impurities remaining after high-temperature sintering, and making the blank dielectric layer (30) during the sintering process more dense, so the loss is smaller and it is not easy to heat, thereby effectively improving the pressure resistance and reliability.

[0018] Fourth, because the heat transfer performance of the inner electrode layer (40) is better than that of the blank dielectric layer (30), the number of continuously arranged inner electrode layers of the same type is increased, which increases the heat transfer channels, effectively compensates for the uneven heating of the product surface and the inside during the sintering process, reduces the heating difference between the reinforced section (50) and the product surface, and makes the blank dielectric layer (30) sinter relatively more dense, thereby reducing the sintering difference with the product surface, and thus effectively improving the reliability and pressure resistance.

[0019] Therefore, the present application provides a new stacking design, which can improve the sintering strength of the reinforced section (50), improve the pressure resistance and current resistance of the reinforced section (50), and reduce the failure rate in the pressure resistance experiment and high-temperature high-pressure experiment, thereby significantly improving the consistency and reliability of the MLCC product. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, more completely understand the present application and its beneficial effects, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a cross-sectional structure diagram of a conventional MLCC product (100); Figure 2 is a cross-sectional structure diagram of an MLCC product (200) in an embodiment; Figure 3A cross-sectional structure diagram of an MLCC product (300) in an embodiment; Figure 4 A cross-sectional structure diagram of an MLCC product (400) in an embodiment; Figure 5 A cross-sectional structure diagram of an MLCC product (500) in an embodiment; Figure 6 A cross-sectional structure diagram of an MLCC product (600) in an embodiment.

[0022] Reference signs: 11, first end electrode; 12, second end electrode; 21, upper protective cover; 22, lower protective cover; 30, blank dielectric layer; 40, internal electrode layer; A, first type electrode layer; B, second type electrode layer; 50, reinforced section; 60, standard section; 70, dielectric interlayer section; a, central axis of the MLCC product. DETAILED DESCRIPTION

[0023] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the spirit of the present application, and that the present application is not limited to the specific embodiments disclosed below.

[0024] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0025] In addition, if the terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0026] In the present application, unless specifically defined otherwise, if there is an appearance of the terms "mount", "connect", "connection", "fixed", and the like, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] In the present application, unless specifically defined otherwise, if there is an appearance of the terms "mount", "connect", "connection", "fixed", and the like, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] It should be noted that if an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a middle element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used in the present application are for illustrative purposes only and do not represent the only implementation.

[0029] In the present application, room temperature refers to indoor temperature, normal temperature or general temperature. Generally, the range of room temperature can be any of the following temperature intervals: 23℃±2℃, 25℃±5℃ or 20℃±5℃.

[0030] The manufacturing method of the MLCC product includes: obtaining a blank dielectric layer by flow casting, and printing a metal electrode (also known as an internal electrode layer) on the blank dielectric layer to form a ceramic dielectric film. In the lamination process, the ceramic dielectric film is stacked in a staggered manner, then placed in a bag for packaging and vacuum sealing, and then subjected to water pressure, cutting, glue removal, sintering, chamfering, end sealing, end burning and electroplating.

[0031] As Figure 1As shown, a conventional MLCC product includes multiple blank dielectric layers (30) and multiple internal electrode layers (40) stacked alternately along the stacking direction, as well as a first end electrode (11) and a second end electrode (12) located on both sides of the internal electrode layer (40). The internal electrode layer (40) includes a first type electrode layer (A) and a second type electrode layer (B) that are alternately arranged and connected to the first end electrode (11) and the second end electrode (12) respectively.

[0032] The capacity of this MLCC product is calculated using the following formula: C = ε × S × (N-1) ÷ T; where C represents the capacity, ε represents the dielectric constant of the blank dielectric layer (30), S represents the area of ​​the first type electrode layer (A) and the second type electrode layer (B) facing each other, and N represents the number of stacked layers ( Figure 1 In this formula, N=16), and T represents the thickness of the medium. From the formula, we know that C is directly proportional to ε, S, and N, and inversely proportional to T. Increasing the directly proportional parameters and decreasing the inversely proportional parameters allows for the design of high-capacity, low-pressure products; conversely, decreasing them allows for the design of low-capacity, high-pressure products. Therefore, (AB)×n( Figure 1 The n=8) stacking design is suitable for medium-high capacity, high capacity and high voltage, and high capacity and low voltage products. The relationship between dielectric thickness T and stacking number N is calculated by considering the rated voltage requirements.

[0033] In MLCC product design, besides size, capacitance and voltage are key parameters. In circuit applications, the performance requirements for MLCC products are becoming increasingly demanding, necessitating the design of high-capacitance, high-voltage products to meet the needs of high-end applications. Voltage withstand capability is directly affected by the dielectric thickness T: the larger T is, the higher the relative voltage withstand. However, dielectric thickness T is inversely proportional to capacitance C; increasing T leads to a decrease in capacitance C. Therefore, when designing high-capacitance, high-voltage products, while ensuring the dielectric constant ε and the face-to-face area S are designed to their maximum fixed values, it is necessary to balance the relationship between the number of stacked layers N and the dielectric thickness T.

[0034] Conventional high-capacity, high-pressure designs often employ stacking at the maximum thickness limit to meet pressure resistance requirements while maintaining capacity and size. However, products manufactured in this way frequently exhibit high failure rates during pressure resistance and high-temperature, high-pressure tests, resulting in poor product consistency and reliability.

[0035] Destructive physical analysis (DPA) of the defective products revealed that most defects were located in the middle region of the stacking sequence. As long as the stacking sequence remained unchanged, even with optimization of the manufacturing process or screening methods, the weakest and most failed areas of the final product were still mostly in the middle region. Further analysis by the applicant identified the following three influencing factors: Firstly, when powered on at high temperatures, the heat dissipation effect is better in the edge region of the stacked sequence than in the middle region; Secondly, in the processing, especially in the glue removal process, the edge area is more likely to discharge organic matter, and the middle area remains relatively more organic matter. After high-temperature sintering, the residual organic matter in the middle area becomes impurities; Thirdly, in the sintering process, the sintering strength and heating effect of the edge area are better than those of the middle area, resulting in relatively large stress in the middle area, which is also prone to defects, high product loss, and easy heating during high-temperature power-on, causing thermal breakdown.

[0036] Therefore, it is necessary to provide an MLCC product, which aims to reduce product failure rate and effectively improve the voltage resistance performance and endurance test time of the MLCC product, so as to make the consistency and reliability of the MLCC product more optimal.

[0037] In some embodiments, as shown in Figure 2 The MLCC product includes a plurality of blank medium layers (30) and a plurality of internal electrode layers (40) alternately stacked in a stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layer (40), and the internal electrode layer (40) includes a first type electrode layer (A) and a second type electrode layer (B) alternately arranged and respectively connected to the first end electrode (11) and the second end electrode (12).

[0038] Among them, the stacking sequence of the internal electrode layer (40) contains 1 reinforcement section (50) in the stacking direction, and the number of the same type of internal electrode layer (A and / or B) continuously arranged in the reinforcement section (50) is 2.

[0039] In the MLCC product provided by the present application, the stacking sequence of the internal electrode layer (40) contains at least one reinforcement section (50) in the stacking direction, and the number of the same type of internal electrode layer continuously arranged in the reinforcement section (50) is not less than 2, which can play the following roles: First, the same type of internal electrode layer (A and / or B) continuously arranged from 1 to 2 or more than 2 is equivalent to increasing the metal electrode by 1 times (or increasing the wire diameter by 1 times), so that the voltage resistance of the internal electrode layer (40) in the reinforcement section (50) is increased, and the reliability is enhanced.

[0040] Second, in a conventional high-capacitance high-voltage design, except for the two outermost inner electrode layers (40), the rest of the inner electrode layers (40) are shared electrodes of two adjacent capacitors, and one inner electrode layer (40) bears the current of two capacitors. In the reinforcement section (50) of the present application, the number of continuously arranged inner electrode layers of the same type is increased, which plays a role of current distribution, and each inner electrode layer (40) only needs to bear the current of one capacitor. The current borne by the inner electrode layer (40) is smaller, which reduces internal heating and loss, effectively reducing the problem of inner electrode layer (40) melting breakdown caused by high temperature.

[0041] Third, during the glue discharge process, the number of continuously arranged inner electrode layers of the same type is increased, which is equivalent to increasing multiple outward glue discharge channels in the reinforcement section (50). Organic matter will be discharged along the direction of the inner electrode layer (40), reducing the organic matter in the reinforcement section (50), thereby reducing the impurities remaining after high-temperature sintering, and making the blank dielectric layer (30) during the sintering process more dense, so the loss is smaller and it is not easy to heat, thereby effectively improving the withstand voltage capability and reliability.

[0042] Fourth, because the heat transfer performance of the inner electrode layer (40) is better than that of the blank dielectric layer (30), the number of continuously arranged inner electrode layers of the same type is increased, which increases the heat transfer channels, effectively compensates for the uneven heating of the product surface and the inside during the sintering process, reduces the heating difference between the reinforcement section (50) and the product surface, and makes the blank dielectric layer (30) sinter relatively more dense, thereby reducing the sintering difference with the product surface, and thus effectively improving the reliability and pressure resistance.

[0043] In summary, the present application provides a new stacking design, which can improve the sintering strength of the reinforcement section (50), improve the pressure resistance and current resistance of the reinforcement section (50), and reduce the failure rate in pressure resistance experiments and high-temperature high-pressure experiments, thereby significantly improving the consistency and reliability of the MLCC product.

[0044] In some embodiments, the reinforcement section (50) is located in the central region of the MLCC product in the stacking direction. It can be understood that in the stacking direction, when the central axis (a) of the MLCC product is located within the reinforcement section (50), it can be considered that the reinforcement section (50) is located in the central region of the MLCC product in the stacking direction.

[0045] As shown in Figure 2 the central axis (a) of the MLCC product and the central axis β (not shown in the figure) of the reinforcement section (50) completely overlap.

[0046] As shown in Figure 3As shown, the central axis (α) of the MLCC product does not completely overlap with the central axis β (not shown) of the reinforcement section (50), but the central axis (α) of the MLCC product is located within the reinforcement section (50).

[0047] Therefore, the above stacking design can effectively enhance the sintering strength of the central region, reduce residual impurities and inherent defects after sintering, improve the pressure resistance and flow resistance of the central region, and thus improve the consistency and reliability of the product.

[0048] In other examples, the reinforced section (50) may not be located in the central region of the MLCC product in the stacking direction, that is, the central axis α of the MLCC product is not located within the reinforced section (50). As a result, the pressure resistance and flow resistance of the MLCC product are also improved.

[0049] In some embodiments, the stacking sequence of the reinforcement sections (50) is a symmetrical sequence. The number of consecutively arranged first type electrode layers (A) is equal to the number of consecutively arranged second type electrode layers (B).

[0050] Therefore, the reinforced section (50) adopts a symmetrical stacking design, which not only makes the electric field distribution more uniform, avoids local concentration of electric field, improves pressure resistance and reliability, but also makes the mechanical structure more stable, effectively releases internal stress, and reduces the risk of delamination and cracking.

[0051] In some embodiments, such as Figure 2 As shown, the number of consecutively arranged inner electrode layers of the same type is two. However, this application is not limited to this; in other examples, the number of consecutively arranged inner electrode layers of the same type can also be 3, 4, 5, 8, or 10, etc. This can also achieve multiple purposes such as increasing the wire diameter, increasing the adhesive discharge channel, and increasing the heat transfer channel. Those skilled in the art can make any selection based on the product's size, capacity, voltage, and other requirements.

[0052] In some embodiments, the symmetric sequence is (AABB)×n1, where n1 is a positive integer representing the number of stacked repeating units (AABB). As an example, n1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, or 50, etc.

[0053] In other examples, the symmetric sequence can also be (AABB)×n1-AA or BB-(AABB)×n1. Specifically, when n1=1, the symmetric sequence can be AABB, AABBAA, or BBAABB. Similarly, the symmetric sequence when n1>1 can be obtained, which will not be elaborated further in this application.

[0054] In other examples, the stacking sequence of the reinforcement section (50) can also be an asymmetric sequence, i.e. the number of consecutively arranged first-type electrode layers (A) is not equal to the number of consecutively arranged second-type electrode layers (B). For example, the asymmetric sequence can be (AABBB)xn1 or (AAABB)xn1, etc.

[0055] In Figure 2 , Figure 3 In some examples, both the first-type electrode layers (A) and the second-type electrode layers (B) in the reinforcement section (50) are consecutively arranged, but the present application is not limited thereto.

[0056] In some examples, only the first-type electrode layers (A) or only the second-type electrode layers (B) are consecutively arranged within the reinforcement section (50), and the stacking sequence thereof can be (AAB)xn1, (AAAB)xn1, (AAAAB)xn1, (ABB)xn1, (ABBB)xn1, or (ABBBB)xn1, etc. Herein, n1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, or 50, etc.

[0057] In some embodiments, the MLCC product further comprises standard sections (60) located on both sides of the reinforcement section (50), and in the standard sections (60), the first-type electrode layers (A) and the second-type electrode layers (B) are stacked in a single alternating manner. That is, the stacking sequence of the standard section (60) is (AB)xn2, wherein n2 is a positive integer representing the stacking number of the repeating unit (AB). As an example, n2 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, or 50, etc.

[0058] It can be understood that the reinforcement section (50) is located in the central region of the MLCC product in the stacking direction, and therefore the number of standard sections (60) is 2, and n2 is the sum of the stacking number of the repeating unit (AB) of the 2 standard sections (60). In addition, in the above stacking sequences ((AABB)xn1, (AB)xn2, etc.), a blank dielectric layer is provided between adjacent internal electrode layers, which will not be described herein again.

[0059] In some embodiments, the total thickness t1 of the reinforcement section (50) is not less than 25% of the total thickness t2 of the standard section (60), i.e. t1≥t2×25%. As an example, t 1= may be 25%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 120%, 140%, 160%, 180%, or 200% of t2. Further, t2×25%≤t1≤t2×150%.

[0060] In some embodiments, the total thickness t1 of the reinforced section (50) is greater than 100 μm, for example, it can be 100 μm, 120 μm, 140 μm, 150 μm, 160 μm, 180 μm, 200 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, 500 μm, 600 μm, 700 μm or 800 μm. Further, the total thickness t1 of the reinforced section (50) is 100 μm to 800 μm.

[0061] Therefore, the larger the total thickness t1 of the reinforced section (50), the better the withstand voltage performance of the MLCC product, the longer the durability test duration, and the lower the product failure rate. By adjusting and controlling the total thickness t1 of the reinforced section (50), the requirements of high withstand voltage, high durability, and low failure rate can be achieved while ensuring high capacity.

[0062] In some embodiments, such as Figure 4 As shown, the stacking sequence also includes a dielectric intercalation segment (70) comprising two consecutive blank dielectric layers (30), which is located within the reinforcement segment (50). Thus, the pressure resistance and flow resistance of the reinforcement segment (50) are further enhanced.

[0063] In some embodiments, such as Figure 5 As shown, the stacking sequence also includes two dielectric intercalation segments (70), each containing two consecutive blank dielectric layers (30), located between the reinforced section (50) and the standard section (60). In some examples, the stacking sequence may also include only one or two dielectric intercalation segments (70) located between the reinforced section (50) and the standard section (60). This further enhances the overall withstand voltage and flow resistance of the MLCC product.

[0064] However, this application is not limited to this. In other examples, the number of media intercalation segments (70) may be 3, 4, 5, 8 or 10; the number of consecutively stacked blank media layers (30) in the media intercalation segments (70) may also be 3, 4, 5, 8 or 10.

[0065] Understandably, the stacking sequence of the inner electrode layer (40) may contain multiple strengthening segments (50) in the stacking direction, such as 2, 3, 4, 5 or 10, etc.

[0066] In some embodiments, such as Figure 6As shown, the stacking sequence of the inner electrode layers (40) comprises 2 reinforced sections (50) and 3 standard sections (60) located on both sides of the 2 reinforced sections (50) in the stacking direction. Within the 2 reinforced sections (50), the stacking sequence is (AABB)xn1. Within the 3 standard sections (60), the stacking sequence is (AB)xn2. Thus, the voltage resistance and current resistance of the MLCC product as a whole are further improved.

[0067] In some embodiments, the stacking sequence further comprises a lower protective cover (22) located at the lowermost layer and an upper protective cover (21) located at the uppermost layer, both of which are stacked by a plurality of blank dielectric layers (30). Thus, structural fixation, physical protection, environmental isolation, and auxiliary heat dissipation can be achieved, thereby improving the reliability, stability, and service life of the MLCC product.

[0068] The following will be further illustrated in conjunction with specific examples and comparative examples. The raw materials involved in the following specific examples and comparative examples, if not specifically stated, can be sourced from the market. The instruments used, if not specifically stated, can be sourced from the market. The processes involved, if not specifically stated, are routinely selected by those skilled in the art.

[0069] Example 1 The MLCC product of this example comprises a plurality of blank dielectric layers (30) and a plurality of inner electrode layers (40) stacked alternately in the stacking direction, and a first end electrode (11) and a second end electrode (12) located on both sides of the inner electrode layers (40), respectively. The inner electrode layers (40) comprise a first type of electrode layer (A) and a second type of electrode layer (B) which are cross-connected and connected to the first end electrode (11) and the second end electrode (12), respectively. The thickness of the blank dielectric layer (30) is 8.5 μm, and the thickness of the inner electrode layer (40) is 1.5 μm.

[0070] In the stacking direction, the MLCC product comprises a lower protective cover (22), a standard section (60), a reinforced section (50), a standard section (60), and an upper protective cover (21) in sequence. Within the reinforced section (50), the stacking sequence of the inner electrode layers (40) is (AABB)xn1, and n1=5. Within the standard section (60), the stacking sequence of the inner electrode layers (40) is (AB)xn2, and n2=86, where n2 is the sum of the stacking numbers of the repeating unit (AB) in the 2 standard sections (60). The lower protective cover (22) is stacked by 24 blank dielectric layers (30), and the upper protective cover (21) is stacked by 24 blank dielectric layers (30).

[0071] In the stacking process, first, a plurality of blank dielectric layers (30) are stacked to form the lower protective cover (22), then 0.5n2 repeating units (AB) are stacked to form a standard section (60), then n1 repeating units (AABB) are stacked to form the reinforced section (50), then 0.5n2 repeating units (AB) are stacked to form another standard section (60), and finally a plurality of blank dielectric layers (30) are stacked to form the upper protective cover (22), thereby forming the above-mentioned stacked structure.

[0072] Embodiment 2 The MLCC product of this embodiment includes a plurality of blank dielectric layers (30) and a plurality of internal electrode layers (40) stacked alternately in the stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layers (40), wherein the internal electrode layers (40) include first electrode layers (A) and second electrode layers (B) arranged in a cross shape and connected to the first end electrode (11) and the second end electrode (12) respectively. The sizes and manufacturing processes of the blank dielectric layers (30), the internal electrode layers (40), the first end electrode (11), and the second end electrode (12) are consistent with those of Embodiment 1.

[0073] In the stacking direction, the MLCC product includes a lower protective cover (22), a standard section (60), a reinforced section (50), a standard section (60), and an upper protective cover (21) in sequence. Within the reinforced section (50), the stacking sequence of the internal electrode layers (40) is (AABB)xn1, and n1=10. Within the standard section (60), the stacking sequence of the internal electrode layers (40) is (AB)xn2, and n2=80, where n2 is the sum of the stacking numbers of the repeating units (AB) in the two standard sections (60). The lower protective cover (22) is stacked by 20 blank dielectric layers (30), and the upper protective cover (21) is stacked by 20 blank dielectric layers (30). By changing the number of blank dielectric layers (30) in the lower protective cover (22) and the upper protective cover (21), the total thickness of the MLCC product is consistent with that of the MLCC product of Embodiment 1.

[0074] Embodiment 3 The MLCC product of this embodiment includes a plurality of blank dielectric layers (30) and a plurality of internal electrode layers (40) stacked alternately in the stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layers (40), wherein the internal electrode layers (40) include first electrode layers (A) and second electrode layers (B) arranged in a cross shape and connected to the first end electrode (11) and the second end electrode (12) respectively. The sizes and manufacturing processes of the blank dielectric layers (30), the internal electrode layers (40), the first end electrode (11), and the second end electrode (12) are consistent with those of Embodiment 1.

[0075] In the stacking direction, the MLCC product comprises, in sequence, a lower protective cover (22), a standard section (60), a reinforced section (50), a standard section (60), and an upper protective cover (21). Within the reinforced section (50), the stacking sequence of the internal electrode layers (40) is (AABB)xn1, n1=20. Within the standard section (60), the stacking sequence of the internal electrode layers (40) is (AB)xn2, n2=70, n2 being the sum of the stacking numbers of the repeating units (AB) in the two standard sections (60). The lower protective cover (22) is stacked by 10 blank dielectric layers (30), and the upper protective cover (21) is stacked by 10 blank dielectric layers (30). By changing the number of blank dielectric layers (30) in the lower protective cover (22) and the upper protective cover (21), the total thickness of the MLCC product is kept consistent with the total thickness of the MLCC product of Example 1.

[0076] Comparative Example 1 The MLCC product of the present comparative example comprises a plurality of blank dielectric layers (30) and a plurality of internal electrode layers (40) stacked alternately in the stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layers (40). The internal electrode layers (40) comprise a first type electrode layer (A) and a second type electrode layer (B) which are arranged in cross and connected to the first end electrode (11) and the second end electrode (12) respectively. The sizes and manufacturing processes of the blank dielectric layers (30), the internal electrode layers (40), the first end electrode (11), and the second end electrode (12) are consistent with those of Example 1.

[0077] In the stacking direction, the stacking sequence of the internal electrode layers (40) of the MLCC product is (AB)xn, n=90. In the stacking process, n repeating units (AB) are sequentially stacked to form the above-mentioned stacking structure.

[0078] Test Example The stacking is performed according to the above-mentioned stacking design, and then the MLCC product is obtained by sequentially performing water pressure, cutting, glue removal, sintering, chamfering, end sealing, end burning, and electroplating in a bag.

[0079] The reliability of 10,000 MLCC products of Examples 1-3 and Comparative Example 1 is verified by pressure resistance test and high temperature and high pressure test, and the test results are shown in Table 1.

[0080] (1) Pressure resistance test: select a device for testing the pressure resistance performance according to the rated voltage, adjust the parameters and the voltage rising rate, place the sample to be tested on a white paper, clamp the two ends of the product with the device clamp, press the start key to test, and release the clamp when the test result appears on the screen. (2) High temperature and high voltage experiment: the prepared sample to be tested is welded on the PCB board, and reflow soldering is performed for 3 times. Then the product is installed on the substrate of the high temperature test box, and the temperature is started to be raised to the rated upper limit temperature of the product, usually 125℃. The voltage is gradually increased to 1.5 times or 2 times of the rated voltage, and the temperature and voltage are continuously applied for 1000h, and the change of leakage current is continuously detected.

[0081] During the degassing process, the organic matter in the product is discharged through high temperature oxidation or cracking. The organic matter in the central region not only diffuses to the upper and lower surfaces of the product for discharge, but also can be discharged to both ends of the product through the inner electrode layer. Compared with Comparative Example 1, the MLCC products provided by Examples 1-3 are more conducive to the rapid discharge of organic matter in the central region, increase the discharge channel, and effectively reduce the residual carbon of the product.

[0082] During the high temperature sintering process after the degassing process, the MLCC product provided by Comparative Example 1 has a better heating effect on the upper and lower surfaces, the ceramic sintering grain is relatively larger, and the ceramic body is more dense, while the heating effect in the middle region is poor, resulting in poor density of the ceramic body and the existence of micro voids. While the MLCC products provided by Examples 1-3 have a reinforcement section (50), which increases the number of the same type of inner electrode layers continuously arranged in the middle region. Since the inner electrode layer (40) has better thermal conductivity than the blank medium layer (30), it effectively compensates for the difference in heating between the middle region and the edge region, reduces the sintering difference between the edge region, and makes the ceramic body relatively more dense.

[0083] As shown in Table 1, the breakdown voltage value of the MLCC products of Examples 1-3 is higher than that of the MLCC products of Comparative Example 1, and the breakdown voltage value gradually increases with the increase of n1 in the reinforcement section (50), and the capacity is also slightly improved under the condition that the total thickness of the MLCC product is unchanged. Further adjusting n1 in the reinforcement section (50) can make the breakdown voltage value of the MLCC product increase by 10%-80% compared with the MLCC product of Comparative Example 1.

[0084] For high temperature and high pressure experiments, the time of the durability test can be compared in any of the following ways: (1) in the same test time, the more the number of failed products (i.e. the higher the failure rate), the shorter the time of the durability test; (2) in the same number of products, the earlier the time of the first failed product, the shorter the time of the durability test. The first comparison method is used in this application. As can be seen from Table 3, when the test time is 60,000 min (i.e. 1,000 h), the failure rate of the MLCC products of Examples 1-3 is significantly lower than that of Comparative Example 1. That is, the time of the durability test of the MLCC products of Examples 1-3 is significantly improved in the process of high temperature and power-on, especially when a large number (thousands, tens of thousands or even more) of MLCC products are powered on at the same time, the failure rate of the MLCC products is greatly reduced, and the consistency and reliability of the products are better.

[0085] Table 1. Comparison of test results of MLCC products of Examples 1-3 and Comparative Example The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0086] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the protection scope of the present application. It should be pointed out that, for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An MLCC product comprising a plurality of blank dielectric layers (30) and a plurality of internal electrode layers (40) alternately stacked along a stacking direction, and a first end electrode (11) and a second end electrode (12) respectively located on both sides of the internal electrode layer (40), wherein the internal electrode layer (40) comprises a first type electrode layer (A) and a second type electrode layer (B) crosswise arranged and respectively connected to the first end electrode (11) and the second end electrode (12), characterized in that: The stacking sequence of the inner electrode layers (40) includes at least one reinforcement section (50) in the stacking direction, and within the reinforcement section (50), there are at least one continuous arrangement of the same type of inner electrode layers (40) with a number not less than 2.

2. The MLCC product as described in claim 1, characterized in that, The reinforced section (50) is located in the central region of the MLCC product in the stacking direction.

3. The MLCC product as described in claim 2, characterized in that, The stacking sequence of the enhanced sections (50) is a symmetrical sequence; wherein the number of consecutively arranged first type electrode layers (A) is equal to the number of consecutively arranged second type electrode layers (B).

4. The MLCC product according to claim 3, characterized in that, The symmetric sequence is (AABB)×n1, (AABB)×n1-AA, or BB-(AABB)×n1, where n1 is a positive integer.

5. The MLCC product according to any one of claims 2-4, characterized in that, The MLCC product also includes standard sections (60) located on both sides of the reinforced section (50), in which a first type of electrode layer (A) and a second type of electrode layer (B) are stacked in a single alternating manner.

6. The MLCC product according to claim 5, characterized in that, The total thickness of the reinforced section (50) is not less than 25% of the total thickness of the standard section (60).

7. The MLCC product according to claim 5, characterized in that, The total thickness of the reinforced section (50) is greater than 100 μm.

8. The MLCC product according to claim 5, characterized in that, The stacking sequence further includes at least one media intercalation segment (70), which comprises at least two consecutive blank media layers (30) and is located within the reinforcement segment (50).

9. The MLCC product according to claim 5, characterized in that, The stacking sequence further includes at least one media intercalation segment (70), which comprises at least two consecutive blank media layers (30) and is located between the reinforcement segment (50) and the standard segment (60).

10. The MLCC product according to any one of claims 2-4, characterized in that, The stacking sequence also includes a lower protective cover (22) at the bottom layer and an upper protective cover (21) at the top layer, both of which are composed of multiple blank dielectric layers (30) stacked together.

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